A young protester was killed Monday after a national guard vehicle "accidentally" ran him over in south Tunisia, raising fears of more social unrest in a region already rocked by weeks of protest.
The death comes as tensions have risen between protesters and security forces outside the El Kamour oil and gas pumping station.
Protesters have been camping outside the desert installation in the Tataouine region for around a month, blocking trucks from entering, to demand a share of local resources and priority for jobs in the sector.
"The health ministry announces the accidental death of a young man, (run over) by the national guard. He was a protester," it told AFP.
Interior ministry spokesman Yasser Mesbah later told reporters the man was hit by a national guard vehicle as it was reversing and died in hospital.
Security forces fired tear gas at demonstrators in El Kamour on Monday as they tried to storm the facility, local radio said, with another protest later reported in the city of Tataouine some 100 kilometres (60 miles) away.
Defence ministry spokesman Belhassen Oueslati said the protesters "used trucks to run down" barricades erected outside the installation.
The health ministry said 50 people were hospitalised after suffering from broken bones or the effects of tear gas during clashes with security forces both in El Kamour and Tataouine.
Mesbah said 13 policemen, six national guardsmen and a member of the civil protection unit were also wounded, with the latter in intensive care.
The demonstrator's death came two days after soldiers fired warning shots in El Kamour to deter protesters.
It was the first escalation of unrest since President Beji Caid Essebsi said earlier this month the army would protect key economic installations from being disrupted by protests over social and labour issues.
Late Sunday, the defence ministry in a statement warned the army would use force against anyone who tried to enter these installations.
The statement warned "all citizens of legal proceedings in the case of clashes with military or security units" and of possible casualties in "the case of a gradual escalation of use of force".
"One must understand that attempting to enter by force an installation protected by the army... is not a peaceful act... It requires a reaction," Oueslati told Express FM radio earlier Monday.
An AFP correspondent said clashes also erupted outside the Tataouine governor's office Monday after residents staged a protest in support of the El Kamour sit-in.
"We only went out to protest after violence erupted in El Kamour," one participant said, asking to remain anonymous.
"We have no problem with the army, who behave in a very civilised way," the protester added.
Two protests were also held in the capital, with demonstrators echoing the rallying cry of Tataouine residents and chanting: "We won't give up!"
"The people of Tataouine are demanding their right to have a share of resources, and Essebsi responds with force," said Tunis protester Marwan.
The Islamist party Ennahdha urged calm but said in a statement that the people's demands are "legitimate".
Mesbah said the headquarters of the national guard in Tataouine was torched and security forces vehicles set ablaze.
An AFP correspondent said the atmosphere remained tense in the city.
Tataouine, around 500 kilometres south of Tunis, has been rocked in recent weeks by protests over unemployment and poverty, and perceived marginalisation of the country's periphery.
Prime Minister Youssef Chahed travelled to the region last month in an attempt to address concerns but was shouted down and forced to leave a heated town hall meeting.
Dozens of protesters interrupted his speech with cries of "Work! Freedom! National Dignity!" -- a slogan from the 2011 uprising that toppled veteran dictator Zine El Abidine Ben Ali.
In January 2016, Tunisia was rocked by some of the worst social unrest since the 2011 protests that sparked the Arab Spring uprisings.
Anger erupted after the death of a 28-year-old unemployed man who was electrocuted when he climbed a power pole while protesting in the central town of Kasserine.
That unrest echoed the public anger after the death of a young fruit seller who set himself on fire in Sidi Bouzid in December 2010 in protest at unemployment and police harassment.